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https://www.readbyqxmd.com/read/28728113/catalase-based-hydrogen-peroxide-biosensor-for-mercury-determination-by-inhibition-measurements
#1
Basant Elsebai, Mariana Emilia Ghica, Mohammed Nooredeen Abbas, Christopher M A Brett
A new amperometric hydrogen peroxide enzyme inhibition biosensor for the indirect determination of toxic mercury ions, Hg(2+), based on catalase immobilized on a glassy carbon electrode surface by cross-linking with glutaraldehyde and bovine serum albumin, is reported. The parameters influencing biosensor performance were optimized, including enzyme loading, the amount of hydrogen peroxide, the applied potential and electrolyte pH. It was shown that the inhibition of catalase by Hg(2+) species is irreversible, with a linear inhibition response between 5×10(-11) and 5×10(-10)M...
July 11, 2017: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/28728109/zero-valent-aluminum-for-reductive-removal-of-aqueous-pollutants-over-a-wide-ph-range-performance-and-mechanism-especially-at-near-neutral-ph
#2
Shiying Yang, Di Zheng, Tengfei Ren, Yixuan Zhang, Jia Xin
Zero-valent aluminum (ZVAl) draws much attention due to its strong reducibility. However, under neutral pH conditions, the reduction ability of ZVAl for pollutant removal has still been suspected because of the formed compact surface film of Al-(hydr)oxide. In this study, unmodified ZVAl was employed to reductively remove aqueous pollutants over a wide pH range, and its performance and mechanism, especially at near-neutral pH, were systematically studied for the first time. Results demonstrated that ZVAl had a wide range of pH applicability from 2 to 12, even in neutral environment...
July 6, 2017: Water Research
https://www.readbyqxmd.com/read/28728087/surface-imprinted-bacterial-cellulose-nanofibers-for-hemoglobin-purification
#3
Monireh Bakhshpour, Emel Tamahkar, Müge Andaç, Adil Denizli
There is a significant need for the development of the novel adsorbents in the field of protein purification. In this study, thin hemoglobin imprinted film (MIP) was fabricated onto the bacterial cellulose nanofibers' (BCNFs) by surface imprinting method using metal ion coordination interactions with N-methacryloyl-(L)-histidinemethylester (MAH) and copper ions. The hemoglobin surface imprinted bacterial cellulose nanofibers (MIP-BCNFs) was applied to selective recognition of hemoglobin and purification from hemolysate...
July 10, 2017: Colloids and Surfaces. B, Biointerfaces
https://www.readbyqxmd.com/read/28727236/structural-and-electronic-flexibility-in-hydrides-of-zintl-phases-with-tetrel-hydrogen-and-tetrel-tetrel-bonds
#4
Henry Auer, Holger Kohlmann
The hydrogenation of Zintl phases enables the formation of new structural entities with main group element-hydrogen bonds in the solid state. The hydrogenation of SrSi, BaSi and BaGe yields the hydrides SrSiH5/3-x, BaSiH5/3-x and BaGeH5/3-x, whose crystal structures were solved by a combination of X-ray, neutron and electron diffraction. Layers of connected HSr4 (HBa4) tetrahedra containing hydride ions alternate with layers of infinite single- and double-chain polyanions, where hydrogen atoms are covalently bound to silicon and germanium...
July 20, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28726953/4-4-di-tert-butyl-6-1h-tetrazol-5-yl-2-2-bipyridine-modification-of-a-highly-selective-n-donor-ligand-for-the-separation-of-trivalent-actinides-from-lanthanides
#5
Martin M Maiwald, Anna T Wagner, Jochen Kratsch, Andrej Skerencak-Frech, Michael Trumm, Andreas Geist, Peter W Roesky, Petra J Panak
In the present work, the complexation and extraction behaviour of 4,4'di-tert-butyl-6-(1H-tetrazol-5-yl)-2,2'-bipyridine (HN4(t)bubipy) towards trivalent actinides (An(iii)) and lanthanides (Ln(iii)) is studied by spectroscopic methods, liquid-liquid extraction, and quantum chemical calculations. The ligand synthesis of HN4(t)bubipy as well as its application in coordination chemistry of the 4f elements is described. Reaction of HN4(t)bubipy with [Ln(NO3)3·6H2O] (Ln = Sm, Eu) results in [H2N4(t)bubipy](+)[Ln(N4(t)bubipy)(NO3)3(H2O)](-)...
July 20, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28726949/spin-reversal-energy-barriers-of-305-k-for-fe-2-d-6-ions-with-linear-ligand-coordination
#6
Lei Xu, Ziba Zangeneh, Ravi Yadav, Stanislav Avdoshenko, Jeroen van den Brink, Anton Jesche, Liviu Hozoi
A remarkably large magnetic anisotropy energy of 305 K is computed by quantum chemistry methods for divalent Fe(2+) d(6) substitutes at Li-ion sites with D6h point-group symmetry within the solid-state matrix of Li3N. This is similar to values calculated by the same approach and confirmed experimentally for linearly coordinated monovalent Fe(1+) d(7) species, among the largest so far in the research area of single-molecule magnets. Our ab initio results therefore mark a new exciting exploration path in the search for superior single-molecule magnets, rooted in the configuration of d(6) transition-metal ions with linear or quasilinear nearest-neighbor coordination...
July 20, 2017: Nanoscale
https://www.readbyqxmd.com/read/28726906/influence-of-local-structure-on-photoluminescence-properties-of-eu-3-doped-ceo2-red-phosphors-through-induced-oxygen-vacancies-by-contrasting-rare-earth-substitutions
#7
Athira K V Raj, P Prabhakar Rao, T S Sreena, T R Aju Thara
A new family of red phosphors, Ce0.9-xRExO2-δ:0.1Eu(3+) (RE = Y and La; x = 0, 0.20, 0.40, 0.60, 0.80, and 0.90), was synthesized by a conventional solid-state route. The influence of contrasting rare earth substitutions (Y and La) in the system was investigated on the local structure and associated photoluminescence properties by various characterization techniques. Both trivalent ion substitutions lead to the same kind of variation during phase transformation from fluorite to the respective parent oxide structure (x ≥ 0...
July 20, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28726884/lithium-dendrite-growth-mechanisms-in-polymer-electrolytes-and-prevention-strategies
#8
Pallab Barai, Kenneth Higa, Venkat Srinivasan
Future lithium-ion batteries must use lithium metal anodes to fulfill the demands of high energy density applications with the potential to enable affordable electric cars with 350-mile range. However, dendrite growth during charging prevents the commercialization of this technology. It has been demonstrated that the presence of a compressive mechanical stress field around a dendritic protrusion prevents growth. Several techniques based on this concept, such as protective layers, externally applied pressure and solid electrolytes have been investigated by other researchers...
July 20, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28726827/nitrogen-reduction-and-functionalization-by-a-multimetallic-uranium-nitride-complex
#9
Marta Falcone, Lucile Chatelain, Rosario Scopelliti, Ivica Živković, Marinella Mazzanti
Molecular nitrogen (N2) is cheap and widely available, but its unreactive nature is a challenge when attempting to functionalize it under mild conditions with other widely available substrates (such as carbon monoxide, CO) to produce value-added compounds. Biological N2 fixation can do this, but the industrial Haber-Bosch process for ammonia production operates under harsh conditions (450 degrees Celsius and 300 bar), even though both processes are thought to involve multimetallic catalytic sites. And although molecular complexes capable of binding and even reducing N2 under mild conditions are known, with co-operativity between metal centres considered crucial for the N2 reduction step, the multimetallic species involved are usually not well defined, and further transformation of N2-binding complexes to achieve N-H or N-C bond formation is rare...
July 19, 2017: Nature
https://www.readbyqxmd.com/read/28726710/using-amine-functionalized-magnetite-hollow-nanospheres-amhns-as-adsorbents-for-heavy-metal-ions
#10
Sen Lin, Lili Liu, Yong Yang, Wei Zhang, Meng Xu, Kuangfei Lin
In this paper, the amine-functionalized magnetite hollow nanospheres (AMHNs), prepared through a facile one-pot synthesis, were used as heavy metal ion adsorbents, whose morphology and physicochemical features were exploring by transmission electron microscopy, vibrating sample magnetometer, X-ray diffraction and Fourier-transform infrared analyses. Its adsorption performances for Pb(2+), Cu(2+), Zn(2+), Ni(2+) and Cd(2+) were studied in detail. The adsorption increased with the increase of initial pH value of the solution and could be obviously affected by ionic strength...
July 2017: Water Science and Technology: a Journal of the International Association on Water Pollution Research
https://www.readbyqxmd.com/read/28726378/ptnps-as-scaffolds-to-regulate-interenzyme-distance-for-construction-of-efficient-enzyme-cascade-amplification-for-ultrasensitive-electrochemical-detection-of-mmp-2
#11
Beibei Kou, Yaqin Chai, Yali Yuan, Ruo Yuan
The high catalytic efficiency of enzyme cascade reaction mainly depends on optimal interenzyme distance regulated by the special scaffolds. In this work, the rigid PtNPs with different sizes were employed as scaffolds to regulate interenzyme distance for efficient enzyme cascade amplification to construct electrochemical biosensor for sensitive detection of matrix metalloproteinases-2 (MMP-2), which overcame the drawbacks of instable construction and sophisticated preparation induced by conventional scaffolds such as metal-organic frameworks (MOFs), DNA nanostructures...
July 20, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28726376/dentritic-cuptpd-catalyst-for-enhanced-electrochemical-oxidation-of-methanol
#12
Xiaoqin Shi, Ying Wen, Xiaoyu Guo, Yuxia Pan, Yuanyuan Ji, Ye Ying, Hai-Feng Yang
The CuPtPd catalyst is designed and synthesized successfully via directly reducing metal ions. The composition, morphology and structure of the as-prepared CuPtPd nanohybrids are characterized by scanning electron microscope (SEM) and transmission electron microscopy (TEM), energy-dispersive spectrometer (EDS), selected-area electron diffraction (SAED), X-ray diffraction (XRD), and inductively coupled plasma atomic emission spectrometry (ICP-AES). By comparison of the electrocatalytic properties of the ternary CuPtPd catalyst with bimetallic catalysts, we find that ternary nanocomposites perform better electrocatalytic and anti-poisoning activity towards oxidation of methanol...
July 20, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28726226/factors-influencing-silver-recovery-and-power-generation-in-bio-electrochemical-reactors
#13
Ngo Anh Dao Ho, Sandhya Babel, Korakot Sombatmankhong
The recovery of silver from Ag(+) solution coupled with power generation was investigated in bio-electrochemical system (BES). In this system, chemical energy existing in the organic matter in the anode chamber can be converted biologically to electrical energy which can be used for the reduction of Ag(+) ions in the cathode chamber. Results showed that type of substrate influenced the metabolic pathway and affected the cell voltage progression, and columbic efficiency. Silver recovery was not affected by increasing initial pH (2...
July 19, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28725970/ion-release-in-ceramic-bearings-for-total-hip-replacement-results-from-an-in-vitro-and-an-in-vivo-study
#14
Jan Philippe Kretzer, Ulrike Mueller, Marcus R Streit, Hartmuth Kiefer, Robert Sonntag, Robert M Streicher, Joern Reinders
INTRODUCTION: Literature on the potential release of trace elements following implantation of Zirconia-platelet toughened alumina (ZPTA) ceramic components is scant. The present study therefore analysed the in vitro and in vivo potential release of ions from ZPTA bearings. MATERIAL AND METHODS: An in vitro and in vivo study was conducted. The in vitro study compared leaching in bovine serum from two groups: ZPTA ceramic heads and Co-28Cr-6Mo alloy heads, both 28-mm diameter...
July 20, 2017: International Orthopaedics
https://www.readbyqxmd.com/read/28725644/pesticides-curbing-soil-fertility-effect-of-complexation-of-free-metal-ions
#15
Sukhmanpreet Kaur, Vijay Kumar, Mohit Chawla, Luigi Cavallo, Albert Poater, Niraj Upadhyay
Researchers have suggested that the reason behind infertility is pernicious effect of broad spectrum pesticides on non target, beneficial microorganism of soil. Here, studying the chelating effect of selective organophosphate and carbamate pesticides with essential metal ions, at all possible combinations of three different pH (4 ± 0.05, 7 ± 0.05 and 9 ± 0.05) and three different temperatures (15 ± 0.5°C, 30 ± 0.5°C and 45 ± 0.5°C), shows very fast rate of reaction which further increases with increase of pH and temperature...
2017: Frontiers in Chemistry
https://www.readbyqxmd.com/read/28725000/trivalent-y-3-ionic-sensor-development-based-on-e-methyl-n-nitrobenzylidene-benzenesulfonohydrazide-mnbbsh-derivatives-modified-with-nafion-matrix
#16
Mohammad Musarraf Hussain, Mohammed M Rahman, Muhammad Nadeem Arshad, Abdullah M Asiri
(E)-Methyl-N'-nitrobenzylidene-benzenesulfonohydrazide (MNBBSH) compounds were synthesized using a condensation procedure from the derivatives of nitrobenzaldehyde and 4-Methyl-benzenesulfonylhydrazine, which crystallized in ethanol and methanol as well as characterized by FTIR, UV-Vis, (1)H-NMR, and (13)C-NMR. MNBBSH structure was confirmed using a single crystal X-ray diffraction technique and used for the detection of selective yttrium ion (Y(3+)) by I-V system. A thin layer of MNBBSH was deposited onto a glassy carbon electrode (GCE) with 5% nafion for the sensitive and selective Y(3+) sensor...
July 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28724964/highly-selective-tungstate-transporter-protein-tupa-from-desulfovibrio-alaskensis-g20
#17
Ana Rita Otrelo-Cardoso, Rashmi R Nair, Márcia A S Correia, Raquel S Correia Cordeiro, Alejandro Panjkovich, Dmitri I Svergun, Teresa Santos-Silva, Maria G Rivas
Molybdenum and tungsten are taken up by bacteria and archaea as their soluble oxyanions through high affinity transport systems belonging to the ATP-binding cassette (ABC) transporters. The component A (ModA/TupA) of these transporters is the first selection gate from which the cell differentiates between MoO4(2-), WO4(2-) and other similar oxyanions. We report the biochemical characterization and the crystal structure of the apo-TupA from Desulfovibrio desulfuricans G20, at 1.4 Å resolution. Small Angle X-ray Scattering data suggests that the protein adopts a closed and more stable conformation upon ion binding...
July 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28724953/antimicrobial-efficacy-and-synergy-of-metal-ions-against-enterococcus-faecium-klebsiella-pneumoniae-and-acinetobacter-baumannii-in-planktonic-and-biofilm-phenotypes
#18
Misha Y Vaidya, Andrew J McBain, Jonathan A Butler, Craig E Banks, Kathryn A Whitehead
The effects of metal ion solutions (silver, copper, platinum, gold and palladium) were determined individually and in combination against Enterococcus faecium, Acinetobacter baumannii and Klebsiella pneumoniae. Platinum, gold and palladium showed the greatest antimicrobial efficacy in zone of inhibition (ZoI) assays. When tested in combinations using ZoI assays, gold/platinum, gold/palladium and platinum/palladium were indicative of synergy. Microbial inhibitory concentration demonstrated platinum and gold against Enterococcus faecium, platinum against Klebsiella pneumoniae and platinum and silver against Acinetobacter baumannii were optimal...
July 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28724886/modulation-of-rna-primer-formation-by-mn-ii-substituted-t7-dna-primase
#19
Stefan Ilic, Sabine R Akabayov, Roy Froimovici, Ron Meiry, Dan Vilenchik, Alfredo Hernandez, Haribabu Arthanari, Barak Akabayov
Lagging strand DNA synthesis by DNA polymerase requires RNA primers produced by DNA primase. The N-terminal primase domain of the gene 4 protein of phage T7 comprises a zinc-binding domain that recognizes a specific DNA sequence and an RNA polymerase domain that catalyzes RNA polymerization. Based on its crystal structure, the RNA polymerase domain contains two Mg(II) ions. Mn(II) substitution leads to elevated RNA primer synthesis by T7 DNA primase. NMR analysis revealed that upon binding Mn(II), T7 DNA primase undergoes conformational changes near the metal cofactor binding site that are not observed when the enzyme binds Mg(II)...
July 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28723955/crystal-structure-and-functional-characterization-of-an-isoaspartyl-dipeptidase-cpsiada-from-colwellia-psychrerythraea-strain-34h
#20
Sun-Ha Park, Chang Woo Lee, Sung Gu Lee, Seung Chul Shin, Hak Jun Kim, Hyun Park, Jun Hyuck Lee
Isoaspartyl dipeptidase (IadA) is an enzyme that catalyzes the hydrolysis of an isoaspartyl dipeptide-like moiety, which can be inappropriately formed in proteins, between the β-carboxyl group side chain of Asp and the amino group of the following amino acid. Here, we have determined the structures of an isoaspartyl dipeptidase (CpsIadA) from Colwellia psychrerythraea, both ligand-free and that complexed with β-isoaspartyl lysine, at 1.85-Å and 2.33-Å resolution, respectively. In both structures, CpsIadA formed an octamer with two Zn ions in the active site...
2017: PloS One
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